GB480185A - Improved sight for firearms such as light or heavy machine guns and the like - Google Patents

Abstract

480,185. Gun sights. VOROBIOFF, A., and HERCKELBOUT, L. L. E. E. Sept. 26, 1936, No. 26120. [Class 92 (ii)] The correction to the angle of training to take account of the relative speed of gun and target is obtained by projecting into the field of view of the sight a luminous grid the vertical elements of which are automatically spaced to suit the relative angular. velocity of gun and target, the elements also representing the correction to be made per unit of range at that angular velocity. If # is the angular correction, # the angular velocity, d the range, and v the average speed of projectile, the lines of the grid are formed by luminous helices 20 each corresponding to a definite range and formed according to the law #=# d/v. The helices 20 are provided on an opaque drum D, Fig. 7, illuminated on the interior and rotated in accordance with # as described later. The apparatus shown in Figs. 3 and 4 is used when a stationary gun is firing at a moving target. The lines seen through a slit 11 by reflection from a mirror system I are spaced to suit the angular velocity. The latter is determined bv a second illuminated helix on a rotary drum P which appears as a moving illuminated horizontal dotted line across the grid when seen through a slit 9. The drum P is rotated by a variable-speed gear comprising a disc M driven continuously at constant speed and a roller 6 on a sliding circular rack L moved by the hand wheel J which rotates the drum D. The rack is feathered on a shaft N which drives the drum P through a differential gear R connected to the gun training gear by a pulley 10 ,to eliminate the effect of training on the rotation of the drum P. The handle J is adjusted until the target is stationary with respect to the moving dotted line and the drum D is then correctly set. Fig. 6 shows the sight applied to a gun mounted on an aircraft steered on a circular course round the target. The angular velocity is measured by a gyroscope Z controlled by a spring 14 and moving the arm 13 of an electrical resistance Y which together with an arm W and resistance U at the sight is included in the circuit of a Wheatstone bridge including a galvenometer X. The drum D is mounted on the shaft T of the arm W and is adjusted until the galvanometer reads zero. If the' course of the ajrcraft is such that the gun needs to be turned slightly, the cable gear 15 moves the arm W and upsets the balance of the bridge which is restored by steering the aircraft until X reads zero again.